1. Technical Field
This invention relates to a broadcasting system, an e-mail delivery device, a delivery method, an e-mail integrated server and a program therefor. And more particularly, this invention relates to the broadcasting system, the e-mail delivery device, the delivery method, the e-mail integrated server and the program therefor that enable to multiplex e-mail data with broadcasting program data and deliver said data.
2. Prior Art of the Invention
As the broadcasting has get digitalized in recent years, peoples are now giving attention to a communication system of the broadcasting characterized by delivering a mass of data to many destinations at high speed, simultaneously and immediately. The e-mailing system can be considered as one of applications effectively utilizing the broadcast communication. The e-mailing system, which needs a receiving route and a sending route for e-mail data, can establish the receiving route in an extremely wide area by means of the broadcasting. In addition, the system has a merit that a user does not need to pay charges for the line used for incoming mails because he can know arrivals of e-mail data immediately without connecting other circuits like a telephone line. Besides, the e-mail data mentioned here contain two parts: one is an information part called a header such as a destination of a message, a destination of a return mail, and etc. that are needed for executing services, and another is a message text called a body.
The first prior art is to deliver e-mail data by the broadcasting, which disclosed in Japanese laid-open publication No. 11-8649. The first prior art has described a mechanism of informing a user's terminal that e-mail data were arrived at a relay center by means of the wireless communication or by broadcasting the broadcasting program data multiplexed with e-mail data (broadcasting data). Provided that the “relay center” defined in the first prior art should be “a station for relaying an e-mail data”. When the user receives the incoming of e-mail data by a terminal such as a television, he can receive the e-mail data by connecting with the Internet through the telephone line, for example.
In addition, the second prior art is disclosed in Japanese laid-open publication No. 11-355349. The second prior art is as follows. A transmitting center sends out a broadcasting program data multiplexed with a flag representing the incoming of e-mail. When a terminal confirms the flag, the terminal sends a request to send the e-mail data to the transmitting center by means of the telephone line or the like. Subsequently, after receiving the request to send the transmitting station multiplexes the corresponding e-mail data with the broadcasting program data, and then transmits said data to the terminal. The terminal can receive the e-mail data multiplexed with the broadcasting program data.
The first and second techniques include the following procedures: the information, for example, representing the incoming of e-mail data, is temporarily added to the broadcasting program data and then the broadcasting program data is sent out. After receiving the response from a terminal corresponding to the information representing the incoming of e-mail data, the transmitting center delivers the e-mail data. Such procedures can be considered to be based on under-mentioned reason.
That is to say, in case of delivering e-mail data using the above-mentioned broadcasting, all of users must share the data transmission band. Therefore, if the number of users increases, the data transmission band per user is restricted. Suppose that e-mail data of 1024 Bytes (−8192 bits) is delivered to ten million users, for example. The required time to transmit the e-mail to whole users is estimated to be about 67 hours in the CS (Communication Satellite) digital broadcasting (at the transmission rate of maximum 34 Mbps), or about 44 hours in the BS (Broadcast Satellite) digital broadcasting (at the transmission rate of maximum 52 Mbps), or about 99 hours in the terrestrial wave digital broadcasting (at the transmission rate of maximum 23 Mbps).
The above estimation examples are based on the assumption that all of the transmission bands of the regular broadcasting are used for the e-mail data. However, since the broadcasting program data must be delivered at the time of operation, the transmission band available for the e-mail data is limited more and the required time get longer. Therefore, if the e-mail data is to be delivered together with the broadcasting program data to all of users, the delivery interval of the e-mails gets too long to finish the delivery of e-mail data as the services.
Accordingly, the first and second prior arts solve the above-mentioned problems by the following method: by adding to the broadcasting program data the information of the incoming of e-mail temporarily, only the necessary (requested) e-mail data is to be delivered alternatively.
However, it is arranged in the prior arts as described above that after receiving information of the incoming of e-mail the receiving-end terminal must send any notification to the sending-end via the other line again. Recently the transmission rate of the line becomes speedier than before. Consequently, even when the e-mail data is received by means of the other line, the receiving-end can receive the mass of e-mail data at high speed. Therefore, it can be said that there is not a merit in the broadcasting that can deliver a mass of data at high-speed. In result, the merits at the time of receiving e-mail data by the broadcasting can be found in the immediacies and the broadcasting communication. The first and second prior arts can satisfy the broadcasting communication, but it is doubtful that those prior arts can satisfy the immediacies. Specifically, knowing the incoming of e-mail data satisfies the immediacies, but the content of the e-mail data are not transmitted. Accordingly, after being informed of the incoming of e-mail data, the receiving-end must execute any operation (any processing) to receive the e-mail data again. It cannot be said that there is sufficient immediacies.